LWG-3621 Remove feature-test macro __cpp_lib_monadic_optional (#2543)

Author: cpplearner

stl/inc/yvals_core.h

@@ -1366,12 +1366,7 @@
 #define __cpp_lib_byteswap                          202110L
 #define __cpp_lib_invoke_r                          202106L
 #define __cpp_lib_is_scoped_enum                    202011L
-
-#ifdef __cpp_lib_concepts
-#define __cpp_lib_monadic_optional 202110L
-#endif // __cpp_lib_concepts
-
-#define __cpp_lib_move_only_function 202110L
+#define __cpp_lib_move_only_function                202110L
 
 #ifdef __cpp_lib_concepts
 #define __cpp_lib_out_ptr                 202106L
@@ -1409,7 +1404,9 @@
 #endif // language mode
 #endif // _M_CEE
 
-#if _HAS_CXX20
+#if _HAS_CXX23 && defined(__cpp_lib_concepts)
+#define __cpp_lib_optional 202110L // P0798R8 Monadic Operations For optional
+#elif _HAS_CXX20 // ^^^ _HAS_CXX23 / _HAS_CXX20 vvv
 #define __cpp_lib_optional 202106L // P2231R1 Completing constexpr In optional And variant
 #elif _HAS_CXX17 // ^^^ _HAS_CXX20 / _HAS_CXX17 vvv
 #define __cpp_lib_optional 201606L // P0307R2 Making Optional Greater Equal Again

tests/std/tests/VSO_0157762_feature_test_macros/test.compile.pass.cpp

@@ -1192,20 +1192,6 @@ STATIC_ASSERT(__cpp_lib_memory_resource == 201603L);
 #endif
 #endif
 
-#if _HAS_CXX23 && !defined(__EDG__) // TRANSITION, EDG concepts support
-#ifndef __cpp_lib_monadic_optional
-#error __cpp_lib_monadic_optional is not defined
-#elif __cpp_lib_monadic_optional != 202110L
-#error __cpp_lib_monadic_optional is not 202110L
-#else
-STATIC_ASSERT(__cpp_lib_monadic_optional == 202110L);
-#endif
-#else
-#ifdef __cpp_lib_monadic_optional
-#error __cpp_lib_monadic_optional is defined
-#endif
-#endif
-
 #if _HAS_CXX23
 #ifndef __cpp_lib_move_only_function
 #error __cpp_lib_move_only_function is not defined
@@ -1264,7 +1250,15 @@ STATIC_ASSERT(__cpp_lib_not_fn == 201603L);
 STATIC_ASSERT(__cpp_lib_null_iterators == 201304L);
 #endif
 
-#if _HAS_CXX20
+#if _HAS_CXX23 && !defined(__EDG__) // TRANSITION, EDG concepts support
+#ifndef __cpp_lib_optional
+#error __cpp_lib_optional is not defined
+#elif __cpp_lib_optional != 202110L
+#error __cpp_lib_optional is not 202110L
+#else
+STATIC_ASSERT(__cpp_lib_optional == 202110L);
+#endif
+#elif _HAS_CXX20
 #ifndef __cpp_lib_optional
 #error __cpp_lib_optional is not defined
 #elif __cpp_lib_optional != 202106L